Re: [PATCH v29 25/32] x86/cet/shstk: Handle thread shadow stack

Borislav Petkov
2021-08-26T16:49:59Z

On Fri, Aug 20, 2021 at 11:11:54AM -0700, Yu-cheng Yu wrote:
> diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c
> index 5993aa8db338..7c1ca2476a5e 100644
> --- a/arch/x86/kernel/shstk.c
> +++ b/arch/x86/kernel/shstk.c
> @@ -75,6 +75,61 @@ int shstk_setup(void)
> return err;
> }
>
> +int shstk_alloc_thread_stack(struct task_struct *tsk, unsigned long clone_flags,
> + unsigned long stack_size)
> +{
> + struct thread_shstk *shstk = &tsk->thread.shstk;
> + struct cet_user_state *state;
> + unsigned long addr;
> +
> + if (!shstk->size)
> + return 0;
> +
> + /*
> + * Earlier clone() does not pass stack_size. Use RLIMIT_STACK and

What is "earlier clone()"?

> + * cap to 4 GB.
> + */

--
Regards/Gruss,
Boris.